High speed repeater



Feb. 26, 1935.- -r5 I 1,992,632

HIGH SPEED REPEATER Filed D60. 13, 1929 INVENTOR [wax/ f fa? W24 ATTORNEY Patented Feb. 26, 1935 UNITED STAT HIGH SPEED REPEATER Louis M. Potts, Evanston, 11., assignor to Teletype Corporation, Chicago, 111., a corporation of Delaware Application Decemher13, 1929, Serial No. 413,875 I 4 Claims.

My invention relates to telegraph systems and more particularly to repeaters employed in such systems, adapted to permit repeated impulses in either direction, depending upon the origin of the impulses. I

In order to permit two-way signalling in a repeater system, the repeaters must be arranged in circuits, so that impulses from one line are repeated only into the other line and not back into the transmitting line. Heretofore, this has been accomplished by providing complicated relay mechanism, marginal in operation.

An object of my invention is to provide novel circuit means for simplifying the apparatus of a two-way signalling'repeater. A further object of my invention is to provide positive means for operating a two-way repeater.

Such two-way repeaters must also be operated at the high speed necessary in telegraph circuits without losing any of the signalling impulses. Accordingly, another object of my invention is to provide novel two-way repeaters operable at a high speed without the loss of any of the signalling impulses.

Other objects of my invention are such as will appear in the detailed description which follows and are defined by the scope of the appended claims.

In the accompanying drawing, the figure'is a circuit diagram of the circuit and apparatus employed in a preferred embodiment of my invention.

A terminal station 1 and a terminal station 2 are interconnected through a two-way repeater 3. The terminal station 1 comprises a transmitter 4, including key operated contacts, shown diagrammatically, which may be a manual key, a keyboard transmitter, automatic tape transmitter or any desired form of transmitting device. The transmitter 4 is connectedto ground at 5 and extends a circuit in its'closed condition through the line relay 6 which is connected in the main signalling line 7 extending to the remotely disposed two-way repeater 3.

45 The line relay 6 is provided with an armature 8 for controlling a printing device 9 of any wellknown construction in accordance with impulses which energize the relay 6.

At the two-way repeaters, the signalling line '7 is connected to one winding 12 of a polarized relay 13 which comprises, in addition to the wind ing 12, a second winding 14 connected in a local circuit, as will be described hereinafter. An armature 15 is jointly controlled by the windings 12 55 and 14, as will be described in detail hereinafter.

The opposite terminal of winding 12 is connected over a conductor 16 to the contact 17 engaged by the armature 18 of a polar relay 20. This circuit is completed through a resistance 22 and 23 to ground at 24.

battery The apparatus at the terminal station 2 is sim-' ilar to the apparatus at terminal station 1, comprising a transmitter 34, including key operated contacts which may be similar in construction to the transmitter 4, a relay 35 connected to 10 ground at 36 and which controls an armature 38 for variably operating a printing device 39 of any well-known construction.

The line relay 35 is connected'over the conductor 41 to the winding 42 of a polar relay 43,'wh ich comprises in addition to winding 42, a second winding 44 connected in a local circuit, as will be described hereinafter and an armature 45'. The opposite terminal of the winding 42'is connected over the conductor 46 to a contact 47 engaged by armature 48 of a polar relay 50. i This circuit is completed over a resistance 52 and battery 53 to ground at 54. r

The windings 14 and 44 of the polar relays 13 and 43, respectively, are in series with each other in a local circuit which extends over a conductor 56, through resistance 57, conductors 58'and 59 to one terminal of battery 60, the opposite terminal of which is connected over conductors 61 and 62 to the opposite terminal of the relay 44, completing the local circuit.

The two-way repeater 3 comprises, in addition to the above mechanism described, ftwoWheatstone bridge circuits 65 and 66. The-bridge 65 comprises a resistance 67 connected in one leg of the bridge and a resistance 68 connected in another leg, the two legs being joined at the terminal 69. Connected across the terminals '10 and 71 of the bridge are the windings of relays and 73 connected in series with each other over conductor 74. The resistances 67 and 68 are preferably equal in value.

In a third leg of the bridge. a resistance '15,: preferably also of the same value as resistances 67 and 68, is connected between'terminals '70 and '76. In the fourth leg of the bridge there is a resistance 77 connected to the contact '78, which is normally not engaged by the armature 15 of the polar relay 13.

conductor 83 to the terminal '71.

Connected be This leg of the bridge ex-"' tween terminals 76 and 69 of the bridge is the b te y 60.

Connected between the terminals '70 and '71 of the bridge are the windings of relays 50 and '73, as stated above.

The resistance '77 in the fourth leg of the bridge is of a value, lower than the resistance '75, so that when its circuit is opened and closed, current between the two relays 50 and '73 is reversed in direction.

The bridge 66 comprises a resistance 84 connected in one leg of the bridgeand a resistance preferably of the same value, connected in another leg of the bridge, these legs being joined at the terminal 86. Across the terminals 8'7 and 83 formed by these two legs of the bridge, are the windings of relays 20 and 82 connected in series with each other over theconductor 89.

Connected in the third leg of the bridge is a resistance which may also: be of the same value as the resistances 84 and 85- and which forms the third terminal 91 of the bridge. In the fourth leg of the bridge is a resistance 92 which is preferably of lower value than the resistance 90 and which is connected to the contact v93,. normally not engaged by the armature 45 of thepolar relay 43. When, however, this contact 93 is engaged by the armature 45, this leg of the bridge is completedover the conductor 94 to the armature 95, which now engages the contact 96 and which'is connected to the terminal 88.

As. in the: case of the bridge 65, the battery 60 is connected across the terminals 86 and 91 of the bridge 66 over the conductors 59 and 61, respectively, and the windings of relays 20 and 82 are connected in series across the terminals 8'7 and 88.

It will be notedthat thefourth leg of the bridge 65 is controlled'by armaturel5 of the polar relay 19 and also by the armature 81 of the relay 82 connected in the other bridge 66, while the fourth leg of the. bridge '66 is controlled by the armature 45 and also by the armature of the first bridge 65. The purpose for this will appear in the description. of the operation, which is to follow.

Normally the contacts 4 and 34 at stations 1 and 2, respectively are closed. As a result of the closed condition of contact 4, a circuit extends from groundv at 5 through the contact 4, relay winding 6, conductor 7, the left hand winding 12' oi the polar relay 13, conductor 16, contact 1'7 and armature 18 in engagement therewith, resistance 22, battery 23, to ground at 24. A circuit is also completed for the local winding 14 from-the terminal of battery 60 over conductor 61 th-roughthe right hand winding 44 of the polar relay 43, conductor 56, right hand winding 14 of the polar relay 13, resistance 57 and conductors 58 and 59 to battery 60.

The resistance 5'7 is so chosen that the current flowing through the right hand winding 14 as a result of the above circuit is overcome by the effect of the current flow through the winding 12 over the line circuit traced above and the winding 12, accordingly, operates the armature 15 to engage the left hand contact as shown.

Due to the fact that the armature 15 is in en gagement with its left hand contact, the fourth leg of the bridge 65 is open. The battery 60, accordingly, has twocircuits in the Wheatstone bridge, one circuit extending over conductor 61 to terminal 69 and thence over resistance 6'7 and 75 back to battery and a second circuit which extends from the terminal 69 of the above circuit through resistance 68 and through the windings of relays '73 and 50 in series with each other over I conductor '74 to terminal '70 and then through resistance '75 back to battery. Current flowing through the relays '73 and 50 as a result of the above circuits operates their armatures 95 and 48, respectively, to engage their contacts 96 and 4'7, respectively.

As in the above case, as a result of the contact 34 at the terminal station 2 being closed, a circuit is completed from ground at 36 through the contact 34, relay 35, line 41,..left hand winding 42 of the relay 43, conductor 46, right hand contact 4'7 and armature 48 of the relay 50, resistance 52 and battery 53 to ground at 54. At this time current also flows through the winding 44 over a local circuit in series with the winding 14, as described in detail above, but as in the case of winding 14, the resistance in this local circuit is so chosen that the current through winding 44 is not sufiicient to overcome the effect of the current in winding 42 and the armature 45 is accordingly held in engagement with its left hand contact and disengaged from contact 93. As a result of this, the fourth leg of the bridge 66, including the resistance 92, is'held open and the battery 60 is accordingly provided with two circuits, one of such circuits extending over conductor 61 to terminal 86 and thence through resistances 84 and 90 to terminal 91 and over conductor 59 to the battery 60'. A second circuit extends from the terminal 86 through the resist ance ,85 and through the windings of the polar relays 82 and 20 in series to the terminal 87, then through resistance 90 and conductor 59 to bat-j tery. The direction of current flow through the windings of relays 82 and 20 as a result of the above circuit is such as to maintain the armatures 81 and 18, respectively, in engagement with their right hand contacts 80 and 17, respectively.

This is the normal condition obtained when no signalling is being carried on. It will now be assumed that the operator at station 1 desires to communicate with the operator at station 2; To this end, at the transmission of the first impulse condition, the contact 4 will be opened,- opening the circuit through the conductor '7 and left hand winding of the relay13, as in the circuit described above. Relay 6 will be deenergized as a result of this circuit and the local relay winding, accordingly, gives the operator at station 1 indications of the signals being transmitted.

The winding 12 of the polar relay 13 will be deenergized as a result of the above action and the current through the winding 14 will now become efiectivetooperate armature 15 to engage with its right hand contact '78, and this will close the fourth. leg of bridge 65, including-resistance '77.

It will be recalled that the resistance 77 is described as being of less value than the resistance '75. As a result the current flowing from the bat-- tery 60 through the resistances 6'7 and '75 will be of lower value than the current in the multiple circuit of lower resistance, including the resistances 68 and 7'7, the circuit for the latter extending from terminal 71, conductor- 83, armature 81 in engagement with its contact 80, conductor '79, armature 15 in engagement with contact '78" or in other words, in reversed direction from that described when the apparatus is in normal condition. Current flowing in reversed direction through these two relays-willoperatetheir armatures.48 and 95 to engage their left-hand contacts conductor 41 vto the station. 2 is broken and the relay 35 at the station 2 accordingly is operated in response, to opening of the key 4 for correspondingly operating the telegraph printer 39. As in the case of the relay 13, when the current through winding 42 .stops..flowing,'the current flowing through the winding 44 over the local circuit becomes effective to engage armaturey45 with its. contact 93. Normally this would close the fourth leg, including resistance 92, of the bridge. 66, but in the present case, the fourth leg of bridge 66 is open at the armature 95, which it will be recalled, has just moved to disengage contact 96. The circuits through the bridge 66, accordingly, remain as they were and the armatures 18 and 81 continue in their position shown in engagement with the contacts 17 and 80, respectively. Had this condition not obtained; that is, had the fourth leg of the bridge 66 been closed, as in the case of the bridge 65, the line circuit for conductor '7 would be opened at the armature 18, thus tying up the circuits at the repeater station.

If the operator at terminal station 1 now again closes the key 4 for transmitting a closed condition, the winding 12 of relay 13 again becomes effective over the circuit traced above to operate armature 15 to disengage its contact 78. This opens the fourth leg of the bridge 65 and the current through the windings of relays 50 and 73 is again in such a direction as to operate armatures 48 and 95 to engage their right hand contacts. The operation of armature 48 to engage its right hand contact 47 closes the circuit of conductor 41 extending to the station 2 and the current through the winding 42 again operates armature 45 to open the fourth leg of the bridge 66 at contact 93. Relay 35 responds to this closed condition to correspondingly operate the printer 39.

Operations originating at the terminal station 2, function in a similar manner to those already described. In connection with impulses originating at station 2 upon the opening of key 34, winding 42 of the polar relay 43 is deenergized and winding 44 becomes effective to operate the armature 45 to engage with contact 93. This closes the fourth leg of the bridge 66, including the resistance 92 and the current through the windings of polar relays 20 and 82 operates the armatures 18 and 81 to disengage their contacts 17 and 80, respectively. As a result of the movement of the armature 18 from contact 17, the cir-, cuit over conductor 7 to terminal station 1 is opened and relay 6 is deenergized accordingly in response to the open line condition originated at terminal station 2 to correspondingly operate printer 9. Disengagement of armature 81 and contact 80 prevents the closing of the fourth leg of bridge 65 when the armature 15 moves to engage contact 78 in response to the open condition of line 7 and of winding 12.

When the key 34 is closed, winding 42 again becomes effective to operate armature 45 from engagement with contact 93, the fourth leg of bridge 66 is opened, and the current flowing through the windings of relays 20 and 82 is again in a direction such that the armatures 18 and 81 move to engage their contacts 17 and 80, respectively. Armature 18 engaging with its contact 17, recloses the line .7 transmitting the closed Vimpulse condition." Winding 12 becomes effective to operatearmature 15 from engagement with its contact 78 before armature 81 becomes efiective to reclose contact 80, maintaining thefourth leg of bridge 65 open during this "operation.

In the eventthat the called operator, for example, the operator at terminal station 2 desires to break in on the calling operator at station. 1, he will open his key 34. If, at the instant the key .34 is opened, the operator. at stationl is transmitting an open line' condition; that is, maintaining his key 4 open, the signalling line41 will already be open at armature 48, as described above, and accordingly the opening of.key 34 has no effect. When, however, the calling operator at station 1 closes his key 4 while the called operator at station 2 maintains his key 34 open, relay winding 42 will be deenergized, armature 45 will move to close contact 93, the fourth leg of the bridge 66 will, accordingly, be closed and.

relay 20 will operate its armature 18 to transmit an open line condition to the calling operator at station 1. Relay 6 of station 1 will respond to this open line condition and the operator, on observing the receipt of an open line condition while he is attempting to transmit a closed line condition, will know that the calling party is attempting to break in.

As will now be clear, simplified circuit means and apparatus are here employed for carrying out positive operations of a two-way repeater. The provision of a Wheatstone bridge circuit renders the operation of the repeater positive and delicately responsive toimpulses by providing polar relays. Quick operation of the armature is obtained, enabling high speed telegraph operations over this circuit.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, the disclosed details are capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish tobe limited to the precise details of the construction set forth, but desire to avail myself of such variations and modifications as come'within the scope of the appended claims.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a telegraph repeater, two line sections; two sets of relays, one set for each line; each set comprising a signal-receiving line relay, a signal-sending local relay, and a reflectionestopping local relay, all of said relays being single-wound polar relays; each line relay responding to line signals in its line section and controlling said local relays, and said signal-sending relay sending signals into theother of said sec-' tions.

2. A system as in claim 1 and including asole local battery which supplies energy for all local relays, namely, both local relays for both line sections.

3. In a telegraph repeater, two signaling lines operation of one signaling relay may control one. of said localcircuits to. cause operation of one. relay of said retransmitting relays, and polar relays in each local circuit and responsive to the operation of the associated signaling relay to reniolve the remaining local circuit from control of its associated signaling relay thereby estopping reflection, each of said relays having a sole operating winding.

4. In a telegraph repeater, a first line section, a first repeating relay having its winding in said first line section, a second repeating relay having its contacts in said first line section, a second line section, a third repeating relay having its winding in said second line section, a fourth repeating relay having its contacts in said second line section, all of said relays being polar relays, each with a single winding and a single contact tongue, a first local system of Wheatstone bridge type formed of local circuits including contacts of said first repeating relay and a winding of said fourth repeating relay whereby said first line section controls said first local system and said first local system controls said second line section, a second local system of Wheatstone bridge type formed of local circuits including contacts of said third repeating relay and a. winding of said second repeating relay whereby said second line section controls said second local system and said second local system controls said first line section, and a further relay having its winding in one of said local systems and its contacts in the other of said local systems whereby an operation of one of said local systems in response to a received line signal will render the other of said local systems unresponsive to line signals thereby estopping reflection.

' LOUIS 'M. POTTS. 

